1. Field of the Invention
The present invention relates to a reactor used in an inverter circuit, a smoothing circuit, an active filter or the like.
2. Description of Related Art
Conventionally, a reactor as shown in FIG. 11A has been used in an inverter circuit, a smoothing circuit and an active filter or the like. As shown in FIG. 11A, a magnetic core portion of the reactor comprises four cores made of lamination and I-shaped which are arranged such that two first cores 1 made of lamination and I-shaped are disposed so as to be parallel to each other, and two second cores 2 made of lamination and I-shaped are disposed so as to be parallel to each other, in which the first cores 1 are disposed perpendicular to the second cores 2 thereby forming a rectangular shape, and as shown in FIG. 11B, gap members 5 are inserted between the first cores 1 and the second cores 2 to construct a magnetic circuit. The reason for combining the four cores made of lamination and I-shaped forming a rectangular shape, instead of combining one core made of lamination and E-shaped and another core made of lamination and I-shaped, is to use a core high in magnetic flux density and magnetic permeability in order to enable downsizing in size and profile.
As a core being low in noise, high in magnetic flux density and magnetic permeability, a silicon steel plate containing 6.5% of silicon, for example, NK SUPER E (registered trademark) provided by NKK Corporation, or the like, has been often used. Such a silicon steel plate as containing some 6% of silicon is almost zero in magneto striction and therefore has advantages of low noise, large saturation magnetic flux density such as 1.8T, and low iron loss at high frequency. However, since a large amount of silicon is contained, it is hard and fragile. Accordingly, silicon steel plates punched out into an E-shape are apt to be chipped or broken. Therefore, four cores each formed of plates cut into an I-shape and laminated are combined as mentioned above thereby constituting a magnetic core of the reactor.
FIGS. 11A and 11B show the cores 1 and 2 made of lamination and I-shaped (hereinafter called xe2x80x9ccoresxe2x80x9d), bobbins 3, and coils 4 (see, FIG. 11A) wound on the bobbins. The gap members 5 are inserted so as to form a suitable gap between the cores 1 and 2. Protrusions 6 are provided extending from ends of the bobbins to position the cores 1 and 2 relative to each other. The reactor is assembled such that the two bobbins 3, 3 shown in FIG. 11B are provided with respective windings, the two cores 2 are inserted into the two bobbins 3, 3, respectively, the gap members 5 and both ends of the two cores 1 are engaged with the protrusions 6 extending from the both ends of the bobbins, positioned, temporarily held and fixed thereto by means of a metal fitting, an adhesive or the like. The ends of the wound coils are soldered to terminals of a terminal block mounted on a metal frame to fix the reactor in, which is not shown.
The above mentioned bobbins are composed of insulating paper such as Nomex or the like. Therefore, it is difficult to position the four cores, which results in causing the cores 1 and 2 to shift from each other, thereby increasing variance of inductance. Moreover, there was also a problem of poor workability because an overflowing portion of an adhesive often used to fix the cores and the gap members to each other in order to reduce noise must be removed.
Further, since there are many constituent parts of the reactor such as parts composing a magnetic circuit of the reactor, parts for connecting the end of the coil to a terminal or the like, the large number of processes to manage the parts has been an obstacle to cost reduction.
Although a reactor using spacers to work as a mechanism to position gap members and cores and also as a receptacle to store an excessive adhesive was disclosed in Japanese Patent No. 2905186 to solve the foregoing problems, further improvements in workability and reduction in the number of parts have been demanded.
It is an object of the present invention to provide a reactor which has a structure enabling cores to be easily positioned relative to each other and easily adhered and fixed in place, ensures good workability, and reduces the number of parts, thereby solving the foregoing problems.
In order to achieve the foregoing object, a first aspect of the present invention relates to a reactor in which two first cores made of lamination and I-shaped and two second cores made of lamination and I-shaped are disposed such that the two first cores are parallel to each other, the two second cores are parallel to each other and that the two second cores having respective coils therearound are perpendicular to the two first cores, thereby forming a rectangular shape, wherein there are provided a first spacer and a second spacer integrated with a terminal block, which are molded of insulating resin, disposed parallel to each other with the two first cores set apart from each other so as to sandwich the two second cores, have on their respective outward side faces two protrusions for positioning each first core and two other protrusions for holding longer sides of each first core with one thereof having at its tip end an engaging mechanism to secure each first core, and which have on their respective inward side faces four protrusions for positioning two neighboring corners of the respective second cores and an elevated portion provided between the four protrusions and elevated in a direction perpendicular to the length of the first cores.
According to a second aspect of the invention, in the first aspect, the first spacer and the second spacer are each formed such that a thickness at portions where the first spacer and the second spacer contact with the first cores and the second cores is equal to a predetermined gap length between the first cores and the second cores.
According to a third aspect of the invention, in the first or second aspect, the terminal block integrally formed on the second spacer is provided with a plurality of terminal insertion holes going therethrough in an insertion direction, and the terminal insertion holes each have a plurality of apertures connecting therewith.
According to a fourth aspect of the invention, in the first to third aspect, a gutter for adhesive to flow into is provided on the first spacer and the second spacer at areas with which the first cores and the second cores are in contact.
According to a fifth aspect of the invention, in the first to fourth aspect, the elevated portion provided on the respective inward side faces of the first spacer and the second spacer is formed so as to contact with two other neighboring corners of the respective second cores, which are not in contact with any of the four protrusions.
According to a sixth aspect of the invention, in the first to fourth aspect, the elevated portion provided on the respective inward side faces of the first spacer and the second spacer is formed so as to contact with one longitudinal surface of the respective second cores, which is not in contact with any of the four protrusions.
According to a seventh aspect of the invention, in the first to sixth aspect, the four protrusions provided on the respective inward side faces of the first spacer and the second spacer are formed such that inner faces thereof hold the second cores and outer faces thereof engage with inner peripheries of the coils wound around the second cores.
According to an eighth aspect of the invention, in the first to seventh aspect, one of the two other protrusions provided on the respective outward side faces of the first spacer and the second spacer has two slits thereby being split into three sections and a middle section of the three sections is provided with elesticity and has the engaging mechanism at its tip end.
As mentioned above, the reactor according to the invention is provided with the the two protrusions for setting the first cores at predetermined positions and the two other protrusions for holding the longer sides of each first core at the respective outward side faces of the first spacer and the second spacer integrally molded with the terminal block, both the first and second spacers being disposed parallel to each other with the first cores set apart from each other so as to sandwich the second cores. One of the two other protrusions for holding the longer sides has at its tip end the engaging mechanism to secure each first core that is positioned with the two protrusions. The four protrusions are provided on the respective inward side faces of the first spacer and the second spacer which face each other so as to position the two neighboring corners of the respective second cores and secure the position of the second cores.
Moreover, the elevated portion provided together with the four protrusions for positioning the two corners, that is three sides of each second core, works to position one remaining side thereof, and also to reinforce the spacers when the gap length between the first core and the second core is small.
Further, the apertures provided around the respective terminal insertion holes connecting therewith work to let varnish smoothly flow out.